Pucch transmission method by mtc device

ABSTRACT

Disclosed is a method for transmitting a physical uplink control channel (PUCCH) by a machine type communication (MTC) device. The PUCCH transmission method comprises the steps of: receiving configuration for independent PUCCH resources at each repetition level of PUCCH; determining a PUCCH resource corresponding to a repetition level, on the basis of the configuration; and repeatedly transmitting the PUCCH, on the determined resource.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to mobile communication.

Related Art

3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) thatis an advancement of UMTS (Universal Mobile Telecommunication System) isbeing introduced with 3GPP release 8. In 3GPP LTE, OFDMA (orthogonalfrequency division multiple access) is used for downlink, and SC-FDMA(single carrier-frequency division multiple access) is used for uplink.The 3GPP LTE adopts MIMO (multiple input multiple output) having maximumfour antennas. Recently, a discussion of 3GPP LTE-A (LTE-Advanced) whichis the evolution of the 3GPP LTE is in progress.

As set forth in 3GPP TS 36.211 V10.4.0, the physical channels in 3GPPLTE may be classified into data channels such as PDSCH (physicaldownlink shared channel) and PUSCH (physical uplink shared channel) andcontrol channels such as PDCCH (physical downlink control channel),PCFICH (physical control format indicator channel), PHICH (physicalhybrid-ARQ indicator channel) and PUCCH (physical uplink controlchannel).

Meanwhile, in recent years, communication, i.e., machine typecommunication (MTC), occurring between devices or between a device and aserver without a human interaction, i.e., a human intervention, isactively under research. The MTC refers to the concept of communicationbased on an existing wireless communication network used by a machinedevice instead of a user equipment (UE) used by a user.

Since the MTC has a feature different from that of a normal UE, aservice optimized to the MTC may differ from a service optimized tohuman-to-human communication. In comparison with a current mobilenetwork communication service, the MTC can be characterized as adifferent market scenario, data communication, less costs and efforts, apotentially great number of MTC devices, wide service areas, low trafficfor each MTC device, etc.

As one of methods of lowering cost per unit of MTC device, the MTCdevice may only use a limited region, i.e. only a subband, regardless ofa system bandwidth of a cell.

The PUCCH among the uplink channels is expected to be transmitted atboth ends based on the entire uplink system bandwidth of the cell.Therefore, according to the existing technology, the MTC device can nottransmit the PUCCH on any one of the subbands.

SUMMARY OF THE INVENTION

Accordingly, the disclosure of the specification has been made in aneffort to solve the problem.

To achieve the foregoing purposes, the disclosure of the presentinvention proposes methods of capable of transmitting the PUCCH in asub-band in which the MTC operates.

In more detail, the present disclosure provides a method fortransmitting a physical uplink control channel (PUCCH). The method maybe performed by a machine type communication (MTC) device and comprise:receiving a configuration for a PUCCH resource, which is independent pera repetition level of the PUCCH; determining a corresponding PUCCHresource based on the configuration; and transmitting repetitions of thePUCCH on the determined resource.

The method may further comprise: determining the number of the repeatedtransmission of the PUCCH according to the repetition level.

The repeated transmission of the PUCCH may be performed if the MTCdevice is located in coverage enhancement region of a cell.

The configuration for the PUCCH resource may include cell-specificvalues.

Meanwhile, the present disclosure also provides a method fortransmitting a physical uplink control channel (PUCCH). The method maybe performed by a machine type communication (MTC) device. The methodmay comprise: transmitting repetitions of the PUCCH on a plurality ofsubframes; and performing a frequency hopping for the PUCCH duringtransmitting the repetitions of the PUCCH. Here, a location of afrequency region on which the PUCCH is transmitted may be maintainedduring n subframes among the plurality of subframes.

The location of the frequency region on which the PUCCH is transmittedmay not be hopped in a unit of a slot.

The location of the frequency region on which the PUCCH is transmittedmay be located on a subband within an uplink system bandwidth.

The frequency hopping may be performed within the subband.

The frequency hopping may be performed in a unit of the subband.

According to the disclosure of the present specification, the problemsof the above-described prior art are solved.

In specific, according to the present disclosure, an MTC deviceoperating on some subbands, rather than the entire system band, mayeffectively configure the PUCCH region, thereby increasing flexibilityin PUSCH RB allocation for a legacy general UE and other MTC devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication system.

FIG. 2 illustrates the architecture of a radio frame according tofrequency division duplex (FDD) of 3rd generation partnership project(3GPP) long term evolution (LTE).

FIG. 3 illustrates the architecture of a downlink radio frame accordingto time division duplex (TDD) in 3GPP LTE.

FIG. 4 illustrates an example resource grid for one uplink or downlinkslot in 3GPP LTE.

FIG. 5 illustrates the architecture of a downlink subframe.

FIG. 6 is an exemplary diagram illustrating a transmission region basedon the PUCCH formation.

FIG. 7 is an example of a subframe having an EPDCCH.

FIG. 8A illustrates an example of Machine Type Communication (MTC).

FIG. 8B illustrates an example of Cell Coverage Extension for an MTCDevice.

FIG. 8c is an exemplary diagram illustrating an example of transmittinga bundle of the uplink channels.

FIG. 9 is an exemplary diagram of illustrating an example in which theMTC device uses only a portion of subband of the downlink systembandwidth of the cell.

FIG. 10A illustrates an example of allocating PUCCHs for an MTC deviceto both ends of the subband, rather than to both ends of the systemband.

FIG. 10B illustrates an example of allocating a PUCCH for an MTC deviceat either end of a subband, rather than at both ends of the system band.

FIG. 11 illustrates an example of signaling a configuration for thePUCCH region with its repetition level of PUCCH.

FIG. 12A and FIG. 12B illustrates an example in which a frequencyhoppling is applied when the PUCCH is repeatedly transmitted.

FIG. 13 is an exemplary diagram illustrating a situation where theuplink subband or the downlink subband is the same among a plurality ofMTC devices.

FIG. 14 is a block diagram illustrating a wireless communications systemin which the disclosure of the present specification is implemented.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, based on 3rd Generation Partnership Project (3GPP) longterm evolution (LTE) or 3GPP LTE-advanced (LTE-A), the present inventionwill be applied. This is just an example, and the present invention maybe applied to various wireless communication systems. Hereinafter, LTEincludes LTE and/or LTE-A.

The technical terms used herein are used to merely describe specificembodiments and should not be construed as limiting the presentinvention. Further, the technical terms used herein should be, unlessdefined otherwise, interpreted as having meanings generally understoodby those skilled in the art but not too broadly or too narrowly.Further, the technical terms used herein, which are determined not toexactly represent the spirit of the invention, should be replaced by orunderstood by such technical terms as being able to be exactlyunderstood by those skilled in the art. Further, the general terms usedherein should be interpreted in the context as defined in thedictionary, but not in an excessively narrowed manner.

The expression of the singular number in the specification includes themeaning of the plural number unless the meaning of the singular numberis definitely different from that of the plural number in the context.In the following description, the term ‘include’ or ‘have’ may representthe existence of a feature, a number, a step, an operation, a component,a part or the combination thereof described in the specification, andmay not exclude the existence or addition of another feature, anothernumber, another step, another operation, another component, another partor the combination thereof.

The terms ‘first’ and ‘second’ are used for the purpose of explanationabout various components, and the components are not limited to theterms ‘first’ and ‘second’. The terms ‘first’ and ‘second’ are only usedto distinguish one component from another component. For example, afirst component may be named as a second component without deviatingfrom the scope of the present invention.

It will be understood that when an element or layer is referred to asbeing “connected to” or “coupled to” another element or layer, it can bedirectly connected or coupled to the other element or layer orintervening elements or layers may be present. In contrast, when anelement is referred to as being “directly connected to” or “directlycoupled to” another element or layer, there are no intervening elementsor layers present.

Hereinafter, embodiments of the present invention will be described ingreater detail with reference to the accompanying drawings. Indescribing the present invention, for ease of understanding, the samereference numerals are used to denote the same components throughout thedrawings, and repetitive description on the same components will beomitted. Detailed description on well-known arts which are determined tomake the gist of the invention unclear will be omitted. The accompanyingdrawings are provided to merely make the spirit of the invention readilyunderstood, but not should be intended to be limiting of the invention.It should be understood that the spirit of the invention may be expandedto its modifications, replacements or equivalents in addition to what isshown in the drawings.

As used herein, ‘base station’ generally refers to a fixed station thatcommunicates with a wireless device and may be denoted by other termssuch as eNB (evolved-NodeB), BTS (base transceiver system), or accesspoint.

As used herein, user equipment (UE) may be stationary or mobile, and maybe denoted by other terms such as device, wireless device, terminal, MS(mobile station), UT (user terminal), SS (subscriber station), MT(mobile terminal) and etc.

FIG. 1 Illustrates a Wireless Communication System.

As seen with reference to FIG. 1, the wireless communication systemincludes at least one base station (BS) 20. Each base station 20provides a communication service to specific geographical areas(generally, referred to as cells) 20 a, 20 b, and 20 c. The cell can befurther divided into a plurality of areas (sectors).

The UE generally belongs to one cell and the cell to which the terminalbelong is referred to as a serving cell. A base station that providesthe communication service to the serving cell is referred to as aserving BS. Since the wireless communication system is a cellularsystem, another cell that neighbors to the serving cell is present.Another cell which neighbors to the serving cell is referred to aneighbor cell. A base station that provides the communication service tothe neighbor cell is referred to as a neighbor BS. The serving cell andthe neighbor cell are relatively decided based on the UE.

Hereinafter, a downlink means communication from the base station 20 tothe UE 10 and an uplink means communication from the UE 10 to the basestation 20. In the downlink, a transmitter may be a part of the basestation 20 and a receiver may be a part of the UE 10. In the uplink, thetransmitter may be a part of the UE 10 and the receiver may be a part ofthe base station 20.

Meanwhile, the wireless communication system may be generally dividedinto a frequency division duplex (FDD) type and a time division duplex(TDD) type. According to the FDD type, uplink transmission and downlinktransmission are achieved while occupying different frequency bands.According to the TDD type, the uplink transmission and the downlinktransmission are achieved at different time while occupying the samefrequency band. A channel response of the TDD type is substantiallyreciprocal. This means that a downlink channel response and an uplinkchannel response are approximately the same as each other in a givenfrequency area. Accordingly, in the TDD based wireless communicationsystem, the downlink channel response may be acquired from the uplinkchannel response. In the TDD type, since an entire frequency band istime-divided in the uplink transmission and the downlink transmission,the downlink transmission by the base station and the uplinktransmission by the terminal may not be performed simultaneously. In theTDD system in which the uplink transmission and the downlinktransmission are divided by the unit of a sub-frame, the uplinktransmission and the downlink transmission are performed in differentsub-frames.

Hereinafter, the LTE system will be described in detail.

FIG. 2 Shows a Downlink Radio Frame Structure According to FDD of 3rdGeneration Partnership Project (3GPP) Long Term Evolution (LTE).

The radio frame of FIG. 2 may be found in the section 5 of 3GPP TS36.211 V10.4.0 (2011-12) “Evolved Universal Terrestrial Radio Access(E-UTRA); Physical Channels and Modulation (Release 10)”.

Referring to FIG. 2, the radio frame consists of 10 subframes. Onesubframe consists of two slots. Slots included in the radio frame arenumbered with slot numbers 0 to 19. A time required to transmit onesubframe is defined as a transmission time interval (TTI). The TTI maybe a scheduling unit for data transmission. For example, one radio framemay have a length of 10 milliseconds (ms), one subframe may have alength of 1 ms, and one slot may have a length of 0.5 ms.

The structure of the radio frame is for exemplary purposes only, andthus the number of subframes included in the radio frame or the numberof slots included in the subframe may change variously.

Meanwhile, one slot may include a plurality of orthogonal frequencydivision multiplexing (OFDM) symbols. The number of OFDM symbolsincluded in one slot may vary depending on a cyclic prefix (CP). Oneslot includes 7 OFDM symbols in case of a normal CP, and one slotincludes 6 OFDM symbols in case of an extended CP. Herein, since the3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in adownlink (DL), the OFDM symbol is only for expressing one symbol periodin a time domain, and there is no limitation in a multiple access schemeor terminologies. For example, the OFDM symbol may also be referred toas another terminology such as a single carrier frequency divisionmultiple access (SC-FDMA) symbol, a symbol period, etc.

FIG. 3 Illustrates an Example Resource Grid for One Uplink or DownlinkSlot in 3GPP LTE.

Referring to FIG. 3, the uplink slot includes a plurality of OFDM(orthogonal frequency division multiplexing) symbols in the time domainand NRB resource blocks (RBs) in the frequency domain. For example, inthe LTE system, the number of resource blocks (RBs), i.e., N_(RB), maybe one from 6 to 110.

Resource block (RB) is a resource allocation unit and includes aplurality of sub-carriers in one slot. For example, if one slot includesseven OFDM symbols in the time domain and the resource block includes 12sub-carriers in the frequency domain, one resource block may include7×12 resource elements (REs).

Meanwhile, the number of sub-carriers in one OFDM symbol may be one of128, 256, 512, 1024, 1536, and 2048.

In 3GPP LTE, the resource grid for one uplink slot shown in FIG. 3 mayalso apply to the resource grid for the downlink slot.

FIG. 4 Illustrates the Architecture of a Downlink Sub-Frame.

In FIG. 4, assuming the normal CP, one slot includes seven OFDM symbols,by way of example.

The DL (downlink) sub-frame is split into a control region and a dataregion in the time domain. The control region includes up to first threeOFDM symbols in the first slot of the sub-frame. However, the number ofOFDM symbols included in the control region may be changed. A PDCCH(physical downlink control channel) and other control channels areallocated to the control region, and a PDSCH is allocated to the dataregion.

The physical channels in 3GPP LTE may be classified into data channelssuch as PDSCH (physical downlink shared channel) and PUSCH (physicaluplink shared channel) and control channels such as PDCCH (physicaldownlink control channel), PCFICH (physical control format indicatorchannel), PHICH (physical hybrid-ARQ indicator channel) and PUCCH(physical uplink control channel).

FIG. 5 Illustrates the Architecture of an Uplink Sub-Frame in 3GPP LTE.

Referring to FIG. 5, the uplink sub-frame may be separated into acontrol region and a data region in the frequency domain. The controlregion is assigned a PUCCH (physical uplink control channel) fortransmission of uplink control information. The data region is assigneda PUSCH (physical uplink shared channel) for transmission of data (insome cases, control information may also be transmitted).

The PUCCH for one terminal is assigned in resource block (RB) pair inthe sub-frame. The resource blocks in the resource block pair take updifferent sub-carriers in each of the first and second slots. Thefrequency occupied by the resource blocks in the resource block pairassigned to the PUCCH is varied with respect to a slot boundary. This isreferred to as the RB pair assigned to the PUCCH having beenfrequency-hopped at the slot boundary.

The terminal may obtain a frequency diversity gain by transmittinguplink control information through different sub-carriers over time. mis a location index that indicates a logical frequency domain locationof a resource block pair assigned to the PUCCH in the sub-frame.

The uplink control information transmitted on the PUCCH includes an HARQ(hybrid automatic repeat request), an ACK (acknowledgement)/NACK(non-acknowledgement), a CQI (channel quality indicator) indicating adownlink channel state, and an SR (scheduling request) that is an uplinkradio resource allocation request.

The PUSCH is mapped with a UL-SCH that is a transport channel. Theuplink data transmitted on the PUSCH may be a transport block that is adata block for the UL-SCH transmitted for the TTI. The transport blockmay be user information. Or, the uplink data may be multiplexed data.The multiplexed data may be data obtained by multiplexing the transportblock for the UL-SCH and control information. For example, the controlinformation multiplexed with the data may include a CQI, a PMI(precoding matrix indicator), an HARQ, and an RI (rank indicator). Or,the uplink data may consist only of control information.

FIG. 6 Illustrates the PUCCH and the PUSCH on an Uplink Subframe.

PUCCH formats will be described with reference to FIG. 6.

The PUCCH format 1 carries the scheduling request (SR). In this case, anon-off keying (OOK) mode may be applied. The PUCCH format 1a carriesacknowledgement/non-acknowledgement (ACK/NACK) modulated in a binaryphase shift keying (BPSK) mode with respect to one codeword. The PUCCHformat 1b carries ACK/NACK modulated in a quadrature phase shift keying(QPSK) mode with respect to two codewords. The PUCCH format 2 carries achannel quality indicator (CQI) modulated in the QPSK mode. The PUCCHformats 2a and 2b carry the CQI and the ACK/NACK.

A table given below carries the PUCCH formats.

TABLE 1 Modulation Total bit count Format mode per subframe DescriptionFormat 1 Undecided Undecided Scheduling request (SR) Format 1a BPSK 1ACK/NACK of 1-bit HARQ, scheduling request (SR) may be present or notpresent Format 1b QPSK 2 ACK/NACK of 2-bit HARQ, scheduling request (SR)may be present or not present Format 2 QPSK 20 In case of extended CP,CSI and 1-bit or 2-bit HARQ ACK/NACK Format 2a QPSK + BPSK 21 CSI and1-bit HARQ ACK/NACK Format 2b QPSK + BPSK 22 CSI and 2-bit HARQ ACK/NACKFormat 3 QPSK 48 Multiple ACKs/NACKs, CSI, and scheduling request (SR)may be present or not present

Each PUCCH format is transmitted while being mapped to a PUCCH region.For example, the PUCCH format 2/2a/2b is transmitted while being mappedto resource blocks (m=0 and 1) of band edges assigned to the UE. A mixedPUCCH RB may be transmitted while being mapped to a resource block(e.g., m=2) adjacent to the resource block to which the PUCCH format2/2a/2b is assigned in a central direction of the band. The PUCCH format1/1a/1b in which the SR and the ACK/NACK are transmitted may be disposedin a resource block in which m=4 or m=5. The number (N(2)RB) of resourceblocks which may be used in the PUCCH format 2/2a/2b in which the CQI istransmitted may be indicated to the UE through a broadcasted signal.

<Carrier Aggregation (CA>

A carrier aggregation system is described hereinafter.

A carrier aggregation system aggregates a plurality of componentcarriers (CCs). A conventional definition of a cell is changed accordingto carrier aggregation. According to carrier aggregation, a cell maydenote a combination of a downlink component carrier and an uplinkcomponent carrier or a downlink component carrier alone.

Further, in carrier aggregation, cells may be divided into a primarycell, a secondary cell, and a serving cell. A primary cell denotes acell operating at a primary frequency, in which a UE performs an initialconnection establishment procedure or a connection reestablishmentprocedure with a BS or which is designated as a primary cell in ahandover procedure. A secondary cell denotes a cell operating at asecondary frequency, which is configured once RRC connection isestablished and is used to provide an additional radio resource.

As described above, the carrier aggregation system may support aplurality of component carriers (CCs), that is, a plurality of servingcells, unlike a single carrier system.

The carrier aggregation system may support cross-carrier scheduling.Cross-carrier scheduling is a scheduling method for performing resourceallocation for a PDSCH transmitted through a different component carrierthrough a PDCCH transmitted through a specific component carrier and/orresource allocation for a PUSCH transmitted through a component carrierdifferent from a component carrier basically linked with the specificcomponent carrier.

<EPDCCH (Enhanced Physical Downlink Control Channel)>

Meanwhile, the PDCCH is monitored in an area restricted to the controlregion in the subframe, and a CRS transmitted in a full band is used todemodulate the PDCCH. As a type of control data is diversified and anamount of control data is increased, scheduling flexibility is decreasedwhen using only the existing PDCCH. Further, in order to decrease anoverhead caused by CRS transmission, an enhanced PDCCH (EPDCCH) has beenintroduced.

FIG. 7 is an Example of a Subframe Having an EPDCCH.

A subframe may include zero or one PDCCH region 410 and zero or moreEPDCCH regions 420 and 430.

The EPDCCH regions 420 and 430 are regions in which a wireless devicemonitors the EPDCCH. The PDCCH region 410 is located in up to first fourOFDM symbols of the subframe, whereas the EPDCCH regions 420 and 430 maybe flexibly scheduled in an OFDM symbol located after the PDCCH region410.

One or more EPDCCH regions 420 and 430 may be assigned to the wirelessdevice. The wireless device may monitor EPDDCH data in the assignedEPDCCH regions 420 and 430.

The number/location/size of the EPDCCH regions 420 and 430 and/orinformation regarding a subframe for monitoring the EPDCCH may bereported by a BS to the wireless device by using a radio resourcecontrol (RRC) message or the like.

In the PDCCH region 410, a PDCCH may be demodulated on the basis of aCRS. In the EPDCCH regions 420 and 430, instead of the CRS, a DM-RS maybe defined for demodulation of the EPDCCH. An associated DM-RS may betransmitted in the EPDCCH regions 420 and 430.

Each of the EPDCCH regions 420 and 430 may be used to schedule adifferent cell. For example, an EPDCCH in the EPDCCH region 420 maycarry scheduling information for a primary cell, and an EPDCCH in theEPDCCH region 430 may carry scheduling information for a secondary cell.

When the EPDCCH is transmitted through multiple antennas in the EPDCCHregions 420 and 430, the same precoding as that used in the EPDCCH maybe applied to a DM-RS in the EPDCCH regions 420 and 430.

Comparing with a case where the PDCCH uses a CCE as a transmissionresource unit, a transmission resource unit for the EPDCCH is called anenhanced control channel element (ECCE). An aggregation level may bedefined as a resource unit for monitoring the EPDCCH. For example, when1 ECCE is a minimum resource for the EPDCCH, it may be defined as anaggregation level L={1, 2, 4, 8, 16}.

In below, an EPDCCH search space may correspond to an EPDCCH region. Oneor more EPDCCH candidates may be monitored at one or more aggregationlevels in the EPDCCH search space.

<MTC (Machine Type Communication) Communication>

Hereinafter, MTC will be described.

FIG. 8a Illustrates an Example of Machine Type Communication (MTC).

The MTC refers to information exchange performed between MTC devices 100via a BS 200 without human interactions or information exchangeperformed between the MTC device 100 and an MTC server 700 via the BS.

The MTC server 700 is an entity for communicating with the MTC device100. The MTC server 700 executes an MTC application, and provides anMTC-specific service to the MTC device.

The MTC server 700 is an entity for communicating with the MTC device100. The MTC server 700 executes an MTC application, and provides anMTC-specific service to the MTC device.

A service provided using the MTC is differentiated from an existingcommunication service requiring human intervention, and its servicerange is various, such as tracking, metering, payment, medical fieldservices, remote controlling, or the like. More specifically, examplesof the service provided using the MTC may include reading a meter,measuring a water level, utilizing a surveillance camera, inventoryreporting of a vending machine, or the like.

The MTC device is characterized in that a transmission data amount issmall and uplink/downlink data transmission/reception occurs sometimesand therefore, it is effective to decrease a unit cost of the MTC deviceand to decrease battery consumption according to a low data transmissionrate. The MTC device is characterized of having a small mobility, andthus is characterized in that a channel environment does almost notchange.

FIG. 8b Illustrates an Example of Cell Coverage Extension for an MTCDevice.

Recently, it has been considered to extend cell coverage of a BS (basestation) for an MTC device 100, and various schemes for extending thecell coverage have been under discussion.

However, when the cell coverage is extended, if the MTC device locatedin the coverage extension region transmits an uplink channel, then theBS has a difficulty in receiving the uplink channel.

FIG. 8c is an Exemplary Diagram Illustrating an Example of Transmittinga Bundle of the Uplink Channels.

As it may be seen with reference to FIG. 8 c, the MTC device which islocated in the coverage extension area 100 repeatedly transmits multiplesubframes (e.g., N sub-frames) on the uplink channel (e.g., PUCCH and/orPUSCH). As described in the above, the uplink channel that is repeatedon the multiple sub-frames is referred to as the bundle of the uplinkchannel.

Meanwhile, the BS receives the bundle of the uplink channel on themultiple sub-frames, and decodes a portion or the whole of the bundle,and thus it is possible to increase the success rate of decoding.

Meanwhile, the BS may also transmit a bundle of downlink channels (e.g.,PDCCH and/or PDSCH) to the MTC device located in the coverage extensionarea on multiple subframes.

FIG. 9 is an Exemplary Diagram of Illustrating an Example in which theMTC Device Uses Only a Portion of Subband of the Downlink SystemBandwidth of the Cell.

As one of methods of lowering cost of the MTC device, the downlinksystem bandwidth of the cell is divided into several subbands of acertain size unit (e.g. 1.4 MHz unit or several RB unit), and the MTCdevice may receive the downlink channel in only one of the severalsubbands, as illustrated in FIG. 9.

Similarly, the uplink system bandwidth of the cell may be divided intoseveral subbands of a certain size, and the MTC device may transmit theuplink channel in any one of the subbands.

Meanwhile, the PUCCH among the uplink channels is transmitted at bothends based on the entire uplink system bandwidth of the cell. Therefore,according to the existing technology, there is a problem that the MTCdevice can not transmit the PUCCH on any subband of the uplink systembandwidth of the cell.

DISCLOSURE OF THE PRESENT INVENTION

Accordingly, the disclosure of the present specification has purposes ofproviding a method to solve the above mentioned problem.

In brief, disclosure of the present specification describes a method formapping and transmitting the uplink channel to allow an MTC device totransmit an uplink channel on a portion of the uplink band (i.e., asubband), rather than the entire uplink system band of the cell.

In other words, the disclosure of the present specification describes amethod for configuring the PUCCH region and mapping the PUCCH to aresource when the MTC device transmits PUCCH on a portion of the uplinkband (i.e., subband), rather than the entire uplink system band of thecell. In this case, a plurality of subbands may be allocated to one MTCdevice, and the MTC device may select any one of the plurality ofsubbands according to the situation. The size of the subband may be thesame for all MTC devices in the cell. The downlink subband and theuplink subband may be respectively configured to the MTC device,respectively. For example, the MTC device 1 may be allocated to theuplink subband 1 and the downlink subband 2, and the MTC device 2 may beallocated to the uplink subband 2 and the downlink subband 2.Alternatively, a plurality of MTC devices may be allocated to the samedownlink subbands, and uplink subbands may be allocated differently.

Meanwhile, in below, the mapping of the PUCCH is described as beingperformed in PRB units. However, when considering frequency hopping oruplink/downlink subband-based hopping, the PRB may be re-interpreted asa virtual RB (VRB). In this case, the VRB may be mapped to the PRBthrough a series of processes.

Hereinafter, the disclosure of the present specification will bedescribed separately in each section.

I. PUCCH Region Configuration

PUCCH format 1/format 2 are transmitted to be mapped from RBscorresponding to both ends of the uplink system bandwidth. In the PUCCHformat 3 series, the PRB position is determined based on the valueconfigured in the RRC stage. Further, the hopping in a unit of slot isapplied to the PUCCH, and the PRB positions transmitted in theeven-numbered slot and the odd-numbered slot may be different. Morespecifically, the PUCCH is mapped symmetrically with respect to thesystem bandwidth (e.g., if the PUCCH is mapped to PRB 0 in the evenslot, then it is mapped to the PRB corresponding to the systembandwidth-1 in the odd number). That is, the PUCCH region (except forPUCCH Format 3) is designed to maximize the contiguous RB allocation ofthe PUSCH. When the MTC device is allocated to a portion of subbands(e.g., six RBs) rather than the entire uplink system band as aneffective operating band, there is a restriction in allocating the PUSCHof the general UE to the contiguous RBs, if the PUCCH region of the MTCdevice is allocated at both ends of the subbands. Further, there may bea restriction in allocating PUSCHs, to contiguous RBs, of other MTCdevices, to which are allocated subbands at positions different from thepositions of the subbands to which the MTC device is allocated. Thiswill be described with reference to the drawings.

FIG. 10A Illustrates an Example of Allocating PUCCHs for an MTC Deviceto Both Ends of the Subband, Rather than to Both Ends of the SystemBand.

As may be seen with reference to FIG. 10A, a legacy UE does not receivethe PUSCH in a consecutive RB due to the subband allocated to the MTCdevice.

Further, as may be seen with reference to FIG. 10A, when the PUCCHregion of the MTC device is located at both ends of the subband, ratherthan at both ends of the uplink system band, the legacy UE is alsodifficult to use the PUSCH region of the subband of the MTC device.

Though the UE is able to transmit PUSCH on non-contiguously allocatedRBs, there may be a restriction on the use of RBG included in thesubband of the MTC device according to the RBG configured based on thesystem bandwidth.

The above mentioned problem may be further aggravated when a pluralityof MTC subbands are configured in the cell's uplink system band.

In order to solve the above mentioned problem, the problem may beavoided or mitigated by redesigning the PUCCH region configuration forthe MTC device. Conventionally, the reason why the PUCCH region isplaced at both ends of the system band is to perform a frequency hoppingin a unit of slot in the PUCCH transmission. Conventionally, PUCCH istransmitted using a pair of RBs of which one is at one end of the systembandwidth in one slot and the other is at the other end of the systembandwidth in a different slot, diversity effect may be expected to beobtained in PUCCH transmission through the hopping in a unit of slot.However, in terms of cost reduction, MTC devices using only somesubbands other than the entire system band are expected to be installedin a fixed place, and further since the MTC device operates only in somesubbands other than the entire system band, and thus it is expected thatthe effect of slot hopping will not be substantial. Therefore, when theMTC device operates only in some subbands other than the entire systemband, it is possible not to perform the frequency hopping in a unit ofslot in the PUCCH transmission. Further in this case, it is alsopossible to consider that the PUCCH region is positioned at one end ofthe system bandwidth, rather than at both ends of the system bandwidth.In this case, the problem may be somewhat alleviated in that the PUSCHof the legacy UE may not be allocated to the contiguous RBs.

FIG. 10B Shows an Example of Allocating a PUCCH for an MTC Device atEither End of a Subband, Rather than at Both Ends of the System Band.

As may be seen with reference to FIG. 10B, when the PUCCH region of theMTC device is positioned at one end of a subband, rather than at bothends of the uplink system band, it is easier to allocate the PUSCH ofthe legacy UE to the contiguous RBs.

In specific, since the PUSCH region of the legacy UE is attached to thePUSCH region for the MTC device, the PUSCH region for the MTC device mayalso be utilized by the legacy UE.

Hereinafter, a detailed scheme for allocating (or configured) the PUCCHarea for the MTC device will be described.

As a first alternative, the PUCCH region for an MTC device using onlysome subbands other than the entire system band may beallocated/configured via a higher layer signal. Theallocation/configuration via the higher layer signaling may be performedby arranging a PUCCH region for the MTC device at both ends of theuplink system bandwidth, arranging the PUCCH region only at a positionabove the uplink system bandwidth, or arranging the PUCCH region only ata position below the uplink system bandwidth. Further, it is possible toconfigure the configuration of whether to frequency-hop the PUCCH in theslot unit to the MTC device through the higher layer signal. However,the frequency hopping in a unit of slot may be possible only when aPUCCH region for the MTC device is located at both ends of the uplinksystem bandwidth. When the PUCCH region is located at both ends of theuplink system bandwidth, it may be assumed that the MTC device mayperform the frequency hopping in a unit of slot even without anadditional signaling. However, when the PUCCH region is located only atone end of the uplink system bandwidth, it may be assumed that the MTCdevice does not perform the frequency hopping in a unit of slot evenwithout an additional signaling.

As a second alternative, the PUCCH region for an MTC device using onlysome subbands, but not the entire system band, may be placed only at oneend of the subband. In this case, when the center RE of the subband orRE in one of the ends for the MTC device is located above the middle ofthe uplink system band, the PUCCH region for the MTC device may belocated a region corresponding to the upper side of the uplink systembandwidth. Alternatively, if the center RE of the subband or RE in oneof the ends for the MTC device is located below the center of the uplinksystem bandwidth, the PUCCH region for the MTC device may be located aregion corresponding to the lower side of the bandwidth of the MTCuplink system.

As a third alternative, a PUCCH region for an MTC device using only aportion of subbands other than the entire system band may be configuredto be disposed only at one end of the uplink system bandwidth. In thiscase, if the center RE of the sub-band or one of the ends RE for the MTCdevice is positioned above the center RE or RE boundary of the RBG towhich the uplink system bandwidth belongs, the PUCCH region for the MTCdevice may be located a region corresponding to the upper side of thesystem bandwidth. Alternatively, if the center RE of the subband or oneof the ends RE for the MTC device is located below the center RE or theRE boundary of the RBG to which the uplink system bandwidth belongs, thePUCCH region for the MTC device may be located a region corresponding tothe lower side of the system bandwidth. If the subband of the MTC devicespans over a plurality of RBGs, the PUCCH region is configured in thesame manner based on the RBG of which a greater portion is spanned over.When the same number of RBs is overlapped with a plurality of RBGs, itmay be considered to configure the PUCCH region based on a small RBGindex.

Through the above mentioned alternative, the flexibility of the PUSCH RBallocation of the legacy UE or other MTC UEs not corresponding to theMTC UL BW may be increased. As an alternative of configuring the PUCCHregion in the MTC UL BW, a deployment for the middle RB region may beadditionally considered in addition to both ends of the UL BW. As aspecific example for a method of signaling to high layer in the above, aplurality of candidates for the MTC UL band (or subband) and/or the PRBregion to which the PUCCH (or HARQ-ACK) is transmitted in the RRC layermay be designated, and then it may be indicate the subband and/or PRBcombination to finally transmit the PUCCH (or HARQ-ACK) through the DCI.In this case, the DCI may correspond to a DL assignment, and theindication information on the candidate configured in the RRC layer inthe DCI may be newly added in an ARI (AN resource indicator) manner orreused with the TPC field. Reuse of the TPC field in the above case ispossible only when the MTC UE does not perform closed-loop power controlusing TPC.

As another alternative, it is possible to consider designating the PRBstart position and/or the end position to which the PUCCH (or HARQ-ACK)is transmitted through the high layer in an offset form. A more specificexample of an offset is that some bits may express whether the offset isbased on the start or the end the system bandwidth or subband of MTCdevice, and the other bits may refer to the offset value to be applied.Meanwhile, if the number of repetitions of the PUCCH is determined basedon a repetition level (or a CE level), then the BS may configure bysignaling the offset to the MTC device independently for each repetitionlevel (or CE level). The repetition level (or CE level) may also includethe case that the repetition is not performed. For example, if therepetition level (or CE level) is zero, the repetition of the PUCCH maynot be performed. Further, if the repetition level (or CE level) is 1,it means that the PUCCH is repeated one time, and thus the same PUCCH isfinally transmitted on two subframes. If the repetition level (or CElevel) is 2, it may mean that the same PUCCH is repeatedly transmittedon four subframes.

Meanwhile, when the PUCCH region is configured to be the same for eachslot, it may be interpreted that the MTC device does not perform thefrequency hopping in a unit of slot in the PUCCH transmission, and inthis case, the MTC device may consider that the PUCCH region isallocated to the same RB for each slot. Alternatively, if the PUCCH areaincludes a plurality of contiguous RBs, then the MTC device may considerthe hopping in a unit of slot among the plurality of RBs.

Meanwhile, The PUCCH region or the subband of MTC device may beconfigured so that the MTC device can be operated only on a specificsubframe or subframe region. The MTC device may not transmit all or apart of the uplink physical channel such as the PUCCH on the sub-framein which the transmission is not allowed or the sub-band or the PUCCHregion is not configured.

1.1 PUCCH Region Configuration for an MTC Device Located in CoverageEnhancement Region

As explained above, as for the MTC device located in the coverageenhancement (CE) region, different repetition levels may be configuredfor each channel. In this case, if uplink physical channel istransmitted with different repetition levels, then its reception powerat an eNB may be different from each other. Specifically, the channelsuch as PUCCH is received at the eNB in the CDM manner, and in thiscase, the eNB may not be able to distinguish a plurality of channels insome implementations when a difference in received power among aplurality of channels is large. This may lead to deterioration of PUCCHdetection performance Therefore, it may consider a method in which CDMis performed only for channels having similar power levels. In thiscase, it may be considered to classify the PUCCH region by repetitionlevel or repetition level set. In this case, classifying the PUCCHregion may be understood as having a different PUCCH region amongchannels which have different repetition levels through FDM/TDM or thelike. For example, it may consider further configuring a PUCCH region inorder of repetition level subsequent to the PUCCH region for an existingnormal UE.

More specifically, the PUCCH configuration may be performedindependently for each repetition level. More specifically, it will bedescribed with reference to FIG. 11.

FIG. 11 Illustrates an Example of Signaling a Configuration for thePUCCH Region with its Repetition Level of PUCCH.

As may be seen with reference to FIG. 11, the BS may signal to the MTCdevice a configuration on the PUCCH resource per a repletion level ofPUCCH.

Then, the MTC device determines the repetition level of the PUCCH anddetermines the number of repeated transmission of the PUCCH based on therepetition level.

Then, the MTC device determines a PUCCH resource corresponding to therepetition level based on the configuration. Further, the MTC devicetransmits the PUCCH by the repetition times on the determined resources.

The PUCCH configuration may refer to include cell-specific configuredvalues. For example, the PUCCH configuration may includedeltaPUCC-shift, which affects to specify the number that can bedistinguished by cyclic shift, n1PUCCH-AN nCS-AN, which can be used tospecify a start position of PUCCH resource including HARQ-ACK, nRB-CQIindicating the number of PRBs per slot that PUCCH resources includingCSI can be included, or the like. In this case, each PUCCH region mayrepresent information of PUCCH resource and PUCCH narrowband informationas parameters.

Meanwhile, the MTC device located in the coverage extension (CE) regionmay consider applying the frequency hopping in a unit of slot again as apart of reducing the number of PUCCH repetitions. In this case, the MTCdevice located in the coverage extension (CE) region may considerperforming frequency hopping in units of a plurality of subframes or aplurality of slots instead of the slot unit as a part to enhance theradio channel estimation performance.

FIG. 12A and FIG. 12B Illustrates an Example in which a FrequencyHoppling is Applied when the PUCCH is Repeatedly Transmitted.

As may be seen with reference to FIG. 12A, when the MTC device performsN (e.g. 8) repetitions on the PUCCH, it may be considered that for thefirst N/2 subframes (e.g. 1 to 4 subframe shown), the PUCCH aretransmitted over a region in which a frequency index in the bandwidth ofthe MTC device is low (high), while for the next N/2 subframes (e.g. 5to 8 subframe shown), the PUCCH are transmitted over a region in which afrequency index in the subband for the MTC device is high (low). Asanother alternative, for the purpose of ensuring continuous allocationof RBs to the PUSCH of a legacy general UE or other MTC devices, it isassumed that the number of subframes in which the repetition of eachPUCCH is transmitted in the two frequency regions is made different fromeach other. As an example, when N is the number with which the PUCCH isrepeatedly transmitted, let's assume N=N1+N2. In this case, it isassumed that N1>N2. It may be assumed to differently configure afrequency region in which the repetition of PUCCH is transmitted on theN1 subframes with a frequency region in which the repetition of PUCCH istransmitted on the next N2 subframes. In this case, N1 and N2 may be apredetermined value or a value configured in a high layer. Meanwhile,the frequency hopping of the PUCCH may be performed once during thePUCCH is repeated N times, or may be performed a plurality of times. Anexample of performing the frequency hopping a plurality of times may beto transmit the repetition of the PUCCH through different frequencyregions based on Nstep configured in advance or by a higher layersignal.

As may be seen with reference to FIG. 12B, when the MTC device performsN (e.g., 8) times of repetitions of the PUCCH, it may be considered thaton the first N/2 subframe (e.g., 1 to 4 subframes shown), the PUCCH istransmitted on a subframe 1 for the MTC device, while on the next N/2subframe (e.g., 5 to 8 subframes shown), the PUCCH is transmitted on asubframe 2.

Alternatively, although not shown, if the MTC device repeatedlytransmits a first PUCCH on N subframes and repeatedly transmits a secondPUCCH on M subframes, then the first PUCCH may be transmitted on thesubband 1 for the MTC device on the N subframe and the second PUCCH maybe transmitted may be transmitted on the subband 2 for the MTC device onthe M subframe

II. PUCCH Resource Mapping

The downlink sub-band and the uplink sub-band of the MTC device may beconfigured to be paired with each other, or may be configuredindependently of each other. As an example, in a situation where theamount of downlink traffic is smaller than the amount of uplink traffic,a case may be considered where a plurality of MTC devices share onedownlink subband but different uplink subbands may be configureddifferently from each other. In this case, if (E)CCE indexes arespecified differently from among a plurality of MTC devices, the PUCCHresources are distinguished, and thus the efficiency of using PUCCHresources may be degraded. For example, let's assume that the samedownlink subband is allocated to MTC device 1 and MTC device 2, and theuplink subbands are allocated differently from each other. Further,let's assume that ECCE1 is allocated to the MTC device 1 and ECCE2 isallocated to the MTC device 2 in the same downlink subband. Then, thePUCCH resource 1 is allocated to the MTC device 1, and the PUCCHresource 2 is allocated to the MTC device 2. However, since the uplinksub-bands are different between the MTC device 1 and the MTC device 2,the PUCCH resources may not necessarily be specified differently fromeach other. That is, it may be better to allocate PUCCH resource 1 toECCE2 in some cases by using ARO or the like in order to completely fillthe PUCCH resources in any one uplink sub-band. On the other hand, itmay be considered for a plurality of MTC devices to be allocated to thesame uplink subbands, but differently allocated to downlink subbands. Inthis case, when the MTC devices perform the PUCCH resource mapping, thedownlink subband regions are different from each other, but the uplinksubbands are the same, and thus the problem may be occurred in that thePUCCH resources may become the same. It will be described with referenceto FIG. 13.

FIG. 13 is an Exemplary Diagram Illustrating a Situation Where theUplink Subband or the Downlink Subband is the Same Among a Plurality ofMTC Devices.

Referring to FIG. 13, it may be configured that for MTC device 1,downlink subband 1 and uplink subband 1 are configured to be pairedwith, and for MTC device 2, downlink subband 2 and uplink subband 1 arepaired with, and for the MTC device 3, the downlink subband 1 and theuplink subband 2 are configured to be paired with, and for the MTCdevice 4, the downlink subband 1 and the uplink subband 2 are configuredto be paired with. In this case, the uplink subband or the downlinksubband of the MTC device may be designated by an RRC signal or throughDCI or the like.

In the example illustrated in FIG. 13, in the MTC device 1 and the MTCdevice 2, the downlink subbands are allocated differently from eachother, but the same uplink subbands are allocated to each other, andthus the problem may be occurred in that the PUCCH resources may becomethe same resource.

As an method to solve the problem, when the BS allocates the samedownlink subbands to an arbitrary MTC device, it may be considered thata pair of downlink subbands and uplink subbands is designated so thatthe uplink subbands can be equally allocated, and signaling thedesignation to the MTC device. However, in the case where this is notavailable or in a case where the pair of the downlink sub-band and theuplink sub-band are not specified but are configured independently ofeach other in order to efficiently manage the system bandwidth, it maybe required to consider that a method for efficiently performing thePUCCH resource allocation, or a method for solving the PUCCH resourcecollision problem occurred from which the same CCE index have been used.

Therefore, the following methods are presented in this section

As a first alternative, for a plurality of MTC devices, if there is aplurality of DL downlink subbands paired with the corresponding uplinksubband, then the BS does not use the PDCCH. Instead, the BS performsdownlink scheduling through an EPDCCH. The BS may prevent the PUCCHresources from colliding with each other when the MTC devices performthe PUCCH resource mapping through the ARO (ACK/NACK Resource Offset) ofthe EPDCCH or the like. The range of ARO values included in the EPDCCHmay be extended to increase the flexibility in PUCCH resource selection.This method may be applied only when the uplink subband and the downlinksub-band of the MTC device are not paired with one-to-one.

As a second alternative, the BS may consider transmitting to include anARO (ACK/NACK Resource Offset) within the PDCCH. This ARO may be usedtogether with the CCE and higher layer signals when the MTC devicedetermines the PUCCH resource. In a situation where one uplink sub-bandis mapped to a plurality of downlink sub-bands, the BS adjusts the valueof the corresponding ARO and thus the PUCCH resource collision may beprevented from each other, even in the case of the same CCE value amongthe plurality of downlink subbands. Further, in a situation where onedownlink subband is mapped to a plurality of uplink subbands, the methodmakes it more flexible for a plurality of MTC devices to use the PUCCHresource utilization in their respective uplink subbands, even in thecase that a plurality of MTC devices uses different CCE values for theone downlink sub-band. Meanwhile, the method may be performed only for aplurality of downlink subbands mapped to the corresponding uplinksubbands. Alternatively, the BS may determine whether the method isapplied or not, and then inform the BS of whether the method has beenapplied to through a higher layer signaling.

As a third alternative, an MTC device using some subbands other than theentire system bandwidth may determine the PUCCH resource by furtherconsidering UEID (e.g., UE-RNTI). This method may be performed only in aplurality of downlink subbands mapped to the corresponding uplinksubbands. Alternatively, the BS may determine whether the method isapplied or not, and then inform the BS of whether the method has beenapplied to through a higher layer signaling.

As a fourth alternative, an MTC device using some subbands other thanthe entire system bandwidth may determine the PUCCH resource by furtherconsidering information on the downlink subbands/uplink subbands. Morespecifically, the downlink sub-band may be a region in which the (E)PDCCH is transmitted in the USS (UE-specific Search Space) or a regionin which the PDSCH is transmitted. For example, if the index of thedownlink subbands/uplink subbands is given based on the entire systembandwidth, then the MTC device may use the corresponding indexes indetermining the PUCCH resources. The method may be performed only in aplurality of downlink subbands mapped to the corresponding uplinksubbands. Alternatively, the BS may determine whether the method isapplied or not, and then inform the BS of whether the method has beenapplied to through a higher layer signaling.

Meanwhile, an indication field such as ARO may be newly added for theMTC device, or the existing TPC field may be reused. Reuse of the TPCfield can be performed only when the MTC device does not perform aclosed loop power control operation using the TPC field. Thedetermination of the PUCCH resource may refer to being divided throughcyclic shift and orthogonal cover code (OCC) within the same PRB, or itmay be indicative of another PRB.

The above mentioned alternatives may be also applied to when a MTCdevice located in the coverage enhancement region performs therepetitive transmission of the uplink channel or the downlink channel.

II-2. PUCCH Resource Mapping of a MTC Device Located in the CoverageEnhancement Region

Meanwhile, the MTC device located in the coverage extension region mayrepeatedly transmit the (E) PDCCH on a plurality of subframes. In thiscase, the value for (E)CCE in the (E) PDCCH transmitted on each subframemay also be changed. The (E)CCE value changing for each of the subframemay be changed to a predetermined pattern to reduce the burden of blinddecoding. In this case, if the repetition levels of the physicalchannels are different from each other, then the end points of thephysical channels may be different from each other, though the startingpoint (subframe start position) of the physical channels is the same. Onthe other hand, the end points of the physical channels are the same,but the starting points of the physical channels may be different fromeach other. If the subframe in which a first PDCCH of a first repetitionlevel is started to be transmitted and the subframe in which in which asecond PDCCH of a second repetition level is started to be transmittedare different, but if the CCEs in the transmission start subframes arethe same, PUCCH resources are determined based on the same CCE, and thuscollisions may occur with each other. In order to prevent the problem,when the (E)PDCCH is repeatedly transmitted, the PUCCH resource may bedetermined based on the (E)CCE of the last transmitted subframe of the(E)PDCCH transmission. Separately or additionally, it may be consideredto introduce a third parameter for determining the PUCCH resource, andthe following is a more specific example of the corresponding case.

As a first alternative, for an MTC device located in coverage extensioncoverage enhancement (CE), the BS may not use the PDCCH. Instead, the BSperforms downlink scheduling through an EPDCCH. The BS may prevent thePUCCH resources from colliding with each other when the MTC devicesperform the PUCCH resource mapping through the ARO (ACK/NACK ResourceOffset) of the EPDCCH. The range of ARO values included in the EPDCCHmay be extended to increase the flexibility in the PUCCH resourceselection.

As a second alternative, the BS may consider transmitting an ARO(ACK/NACK Resource Offset) within the PDCCH. This ARO may be usedtogether with the CCE and higher layer signals when the MTC devicedetermines the PUCCH resource. The BS may prevent the PUCCH resourcesfrom colliding by adjusting the value of the corresponding ARO, eventhough the initial CCE values are the same among the channels havingdifferent repeat levels. The BS may inform the MTC device of whether themethod has been applied or not through a higher layer signal.

As a third alternative, the MTC device located in the coverage extensionarea may determine the PUCCH resource by further considering the UE ID(e.g., UE-RNTI). The BS may inform the MTC device of whether the methodhas been applied or not through a higher layer signal.

As a fourth alternative, the MTC device located in the coverageextension area may determine the PUCCH resource by further consideringthe information on the repetition level. The BS may inform the MTCdevice of whether the method has been applied or not through a higherlayer signal.

As a fifth alternative, the MTC device located in the coverage extensionarea may determine the PUCCH resource by further considering the starttime or the end time of the (E) PDCCH transmission. The start/end timemay be represented by a subframe index type or an SC-FDMA symbol indexor a slot index.

Some or all of the alternatives may be combined. As one example, the MTCdevice may determine the PUCCH resource by further considering therepetition level with the ARO. The indication field, such as the ARO,may be newly added to the PDCCH for the MTC device, or may reuse theexisting TPC field. Reuse of the TPC field can be performed only whenthe MTC device does not perform a closed loop power control operationusing the TPC field. The determination of the PUCCH resource may referto being divided through cyclic shift and orthogonal cover code (OCC)within the same PRB, or it may be indicative of another PRB. As a morespecific example, the BS may configure the downlink subband to be usedwith which the MTC device determines the PUCCH resource or the locationof the RB to which the PUCCH is to be transmitted. The MTC device maydetermine a region to transmit the PUCCH including the HARQ-ACKaccording to the downlink subband for performing the USS monitoring orthe downlink subband on which the PDSCH is received.

The above mentioned embodiments of the present invention may beimplemented by various means. For example, embodiments of the presentinvention may be implemented by hardware, firmware, software, orcombinations thereof. Specifically, embodiments of the present inventionwill be explained by referring to the following diagram.

FIG. 14 is a Block Diagram Illustrating a Wireless Communications Systemin which the Disclosure of the Present Specification is Implemented.

A BS 200 includes a processor 201, a memory 202 and an RF (radiofrequency) unit 203. The memory 202 is connected to the processor 201,and stores various information for driving the processor 201. The RFunit 203 is connected to the processor 201, and transmits and/orreceives radio signals. The processor 201 implements proposed functions,processes and/or methods. In the above mentioned embodiment, theoperation of the BS 50 can be implemented by the processor 201.

A MTC device 100 includes a processor 101, a memory 102 and an RF unit103. The memory 102 is connected to the processor 61, and stores variousinformation for driving the processor 101. The RF unit 103 is connectedto the processor 101, and transmits and/or receives radio signals. Theprocessor 101 implements proposed functions, processes and/or methods.

The processor may include Application-Specific Integrated Circuits(ASICs), other chipsets, logic circuits, and/or data processors. Thememory may include Read-Only Memory (ROM), Random Access Memory (RAM),flash memory, memory cards, storage media and/or other storage devices.The RF unit may include a baseband circuit for processing a radiosignal. When the above-described embodiment is implemented in software,the above-described scheme may be implemented using a module (process orfunction) which performs the above function. The module may be stored inthe memory and executed by the processor. The memory may be disposed tothe processor internally or externally and connected to the processorusing a variety of well-known means.

In the above exemplary systems, although the methods have been describedon the basis of the flowcharts using a series of the steps or blocks,the present invention is not limited to the sequence of the steps, andsome of the steps may be performed at different sequences from theremaining steps or may be performed simultaneously with the remainingsteps. Furthermore, those skilled in the art will understand that thesteps shown in the flowcharts are not exclusive and may include othersteps or one or more steps of the flowcharts may be deleted withoutaffecting the scope of the present invention.

1-5. (canceled)
 6. A method for transmitting a physical uplink controlchannel (PUCCH), the method performed by a wireless device andcomprising: transmitting repetitions of the PUCCH on a plurality ofsubframes; and performing a frequency hopping for the PUCCH duringtransmitting the repetitions of the PUCCH, wherein a location of afrequency region on which the PUCCH is transmitted is maintained duringn subframes among the plurality of subframes.
 7. The method of claim 6,wherein the location of the frequency region on which the PUCCH istransmitted is not hopped per a slot.
 8. The method of claim 6, whereinthe location of the frequency region on which the PUCCH is transmittedis located on a subband within an uplink system bandwidth.
 9. The methodof claim 8, wherein the frequency hopping is performed within thesubband or in a unit of the subband.
 10. (canceled)
 11. The method ofclaim 6, further comprising: determining the number of the repetitionsof the PUCCH according to a repetition level.
 12. The method of claim 6,wherein the repeated transmissions of the PUCCH are performed if thewireless device is located in coverage enhancement region of a cell. 13.The method of claim 6, further comprising: receiving a configuration fora PUCCH resource, wherein the configuration for the PUCCH resource isspecified according a repetition level of the PUCCH; and determining acorresponding PUCCH resource based on the configuration.
 14. The methodof claim 13, wherein the configuration for the PUCCH resource includescell-specific values.
 15. The method of claim 14, wherein thecell-specific values include at least one of: a parameter for specifyingthe number of the PUCCHs distinguishable by a cyclic shift, a parameterfor specifying a start location of the PUCCH resource including a hybridautomatic repeat request-acknowledgement (HARQ-ACK) and a parameter forspecifying the number of physical resource blocks (PRBs) per a slot onwhich the PUCCH resource including a channel state information (CSI).16. A wireless device for transmitting a physical uplink control channel(PUCCH), comprising: a transceiver; and a processor operativelyconnected to the transceiver and configured to: transmit repetitions ofthe PUCCH on a plurality of subframes; and perform a frequency hoppingfor the PUCCH during transmitting the repetitions of the PUCCH, whereina location of a frequency region on which the PUCCH is transmitted ismaintained during n subframes among the plurality of subframes.
 17. Thewireless device of claim 16, wherein the location of the frequencyregion on which the PUCCH is transmitted is not hopped per a slot. 18.The wireless device of claim 16, wherein the location of the frequencyregion on which the PUCCH is transmitted is located on a subband withinan uplink system bandwidth.
 19. The wireless device of claim 18, whereinthe frequency hopping is performed within the subband or in a unit ofthe subband.
 20. The wireless device of claim 16, wherein the processoris further configured to: determine the number of the repetitions of thePUCCH according to a repetition level.
 21. The wireless device of claim16, wherein the repeated transmissions of the PUCCH are performed if thewireless device is located in coverage enhancement region of a cell.